Field
The present disclosure relates generally to energy storage devices and systems, such as batteries and capacitors modules and systems, including ultracapacitors and super-capacitors, and in particular, capacitors or batteries deployed in modules, each module containing some number of battery and/or capacitor cells.
Description of the Related Art
Various systems and techniques exist for balancing the voltage of individual cells in an energy storage system by discharging an excess cell voltage. However, prior approaches do not fully and efficiently dissipate excess cell voltage and require expensive components.
Additionally, systems and techniques for balancing modules may not be capable of discharging negative voltages in one or more of the individual cells that form the modules being balanced. These negative voltages may present problems in such systems.
Additionally, systems and techniques exist for detecting failure in an energy storage system and issuing an alarm, but they often fail due to excess voltages from the energy storage system. In some systems and techniques, separate but redundant alarm systems may be used to monitor and alert for various module-wide conditions. For example, an open cell condition in a module (e.g., where an entire voltage of the module, up to 750 volts (V) in this case) may be expressed on the alarm circuit of the module and may destroy the alarm circuit. Thus, a redundant circuit, capable of surviving a high voltage (e.g., 750V) is needed to provide a sustained alarm in varied conditions.